What it is and what it does
The Siemens SENTRON 5SY7650-7 is a 4-pole miniature circuit breaker (3P+N) with a C tripping characteristic, rated 50 A at 35 °C and 400 V AC. It breaks fault currents up to 15 kA per EN 60898 and 20 kA per IEC 60947-2, which means it safely clears high-energy faults in industrial panel feeders without cascading upstream. The C curve (5–10× In) handles moderate inrush from motor starters and transformer primaries — a common choice for mixed loads in mechanical engineering and industry panels.
Ratings and what they mean for fit
The 50 A rating is at 35 °C ambient. In a warm cabinet — say 45 °C — the breaker must be derated to 47 A; at 50 °C it drops to 45.95 A, and at 60 °C to 43.8 A. If your panel runs hot, size the load below these derated figures or the breaker may nuisance-trip. The 15 kA (EN 60898) / 20 kA (IEC 60947-2) breaking capacity tells you the maximum fault current it can interrupt at 400 V AC — enough for most industrial sub-distribution boards with a transformer upstream. Pollution degree 3 and overvoltage category III suit fixed installations in industrial environments.
Mounting and integration
Snaps onto DIN rail via the quick assembly system; 4 modular width units (72 mm wide) and 70 mm installation depth leave room for wiring in a standard enclosure. Mounting position is any — no orientation restrictions. Combined terminals top and bottom accept supply from either end, and the breaker is sealable for tamper-proof installations. Touch protection is built in (IP20 with connected conductors).